Fluid pressure brake



Sept. 26 1933. j

C. C. FARM ER FLUID PRES SURE BRAKE Filed Feb. 3, 1932 Fig. I

I N VEN TOR.

CLYDE C FARMER:

A TTORNE Y.

Patented Sept. 26, 1933 I 1 g UNITED STATES PATIENT orricsj FLUIDPRESSURE BRAKE Clyde 0. Farmer, Pittsburgh, Pa., assignor to TheWestinghouse Air Brake Company, Wilmerding, Pa., a corporation ofPennsylvania Application February 3, 1932. Serial No. 590,564

4 Claims. (Cl. 303-70) This invention relates to fluid pressure brakes,is a member l l, having a stem 15, which extends and more particularlyto a triple valve device rearwardly through a-bore in the piston stem 9,for a fluid pressure brake system, which is opand into a recess 16, cutin the valve 8 at its forerated upon a reduction in brake pipe pressureward end. The stem 15 is operatively connectto supply fluid underpressure to the brake cylined to the valve 8, through a pin 17. A coilspring der, and upon an increase in brake pipe pressure 18 surrounds thestem 15 and is mounted in a re to release fluid from the brake cylinder.cess in the piston stem 9, so as to oppose inward After the triple valvedevice has been operated movement of the diaphragm 12 relative to theupon a reduction in brake pipe pressure to supply piston 4. I fluidunder pressure to the brake cylinder, and In operation, with the movingparts of-.the 65;;

the brake pipe pressure is increased to eflect the triple valve devicein release position, as shown release movement of the triple valvemoving in Fig. 1, when the brake pipe 3 is chargedwith parts, the mainslide valve of the triple valve fluid under pressure in the usualmanner, fluid device may sometimes have such high resistance underpressure flows from the brake pipe to the to movement that the valvewill stick and thus piston chamber 2 of the triple valve device, and 70-prevent the release movement of the parts, unless thence through theusual feed groove 19 around the increase in brake pipe pressure is veryrapid. the piston to the valve chamber 5 and the auxili- The principalobject of my invention is to proany reservoir 6, thus charging theauxiliary reservide a triple valve device with means operative voir withfluid under pressure. In release posi- 20 upon an increase in brake pipepressure in retion, as shown in Fig.- 1, the brake cylinder 20 75;.-

leasing the brakes to facilitate and ensure the is connected to theatmospheric exhaust port 21, release movement, by venting fluid underpresthrough pipe 22, passage 23 and cavity 24 in the sure from theauxiliary reservoir. main slide valve 7 y a s In the accompanyingdrawing; Fig.1 is a sec- When it is desired to effect a service applica-25 tional view of a triple valve device embodying my tion of the brakes,a reduction in brake pipe 801,

invention, and showing the moving parts of the pressure is effected,causing outward movement triple valve device in release position; Fig. 2a or" the piston 4 to closethe feed groove 19 and similar view, showingthe moving parts of the moving the graduatingvalve 8 relatively to thetriple valve device in service application position; main slidevalve 7,so that the service port 25 in and Fig. 3 a similar view, showng themoving the'mainslide valve is uncovered. The.further. 85 1;

parts of the triple valve device in the positions movement of the piston4 then operates the main initially assumed after the brake pipe pressureslide valve '7 and moves same to service applicahas been increased toeffect the release or" the tion position, as shown in Fig. 2,.in whichthe brakes. service port 25 registers withbrake cylinder pas- 1 having apiston chamber 2, connected to the in the usual manner, from valvechamber 5 and brake pipe 3 and containing piston 4, and having theauxiliary reservoir 6 to the brake cylinder a valve chamber 5 at theopposite side of the pis- 20.

ton 4, connected to the auxiliary reservoir 6 and When the auxiliaryreservoir pressure has been 40 containing a main slide valve 7, and anauxiliary reduced by flow to the brake cylinder, to a degree 955 orgraduating slide valve 8 having a movement slightly less than thereduced brake pipe pressure, 7 relative to the main slide valve. Saidvalves are the piston 4 moves the graduating valve 8 to lap operated inthe usual manner, by the piston 4, position, so as to close off theservice port 25, the through piston stem 9. lap position of the pistonbeing the same as that According to my invention, a lost motion spaceshown in Fig. 3.

is provided between the ends of the graduating When the brake pipepressure is increased to valve 8 and the operating shoulders 10 and 11effect the releaseof the brakes, after the brakes of the piston stem 9,so that the piston stem has have been applied in the manner above deamovement relative to the valve. scribed, if the increase in brake pipepressure is piston 4 is a movable abutment, preferably in the therelease movement of the main slide valve '7, form of a flexiblediaphragm 12, which may be then the operation of my release ensuringmeans secured in place by means of a threaded collar will act to ensuresuch movement inthe follow 13, having screw-threaded engagement in theing manner.

The triple valve device may comprise a casing sage 23. Fluid underpressure is then' supplied, v90.3."-

Mounted in an annular recess provided in the not sufficient to cause thepiston 4 to at once start piston. Secured centrally to the diaphragm 12When the brake pipe pressureis increased, a.

claim as new and desire Patent, is:

differential fluid pressure is created on the flexible diaphragm 12,which is subject to the opposing pressures of the auxiliary reservoirand the brake pipe. When the brake pipe pressure has been increasedabove the auxiliary reservoir pressure a predetermined degree,sufiicient to overcome the pressure of the spring 18, the diaphragm 12will be flexed inwardly to the position shown in Fig. 3, so that thegraduating valve 8 is moved relatively to the piston 4 and the pistonstem 9 to the position shown in Fig. 3. In this position, a port '26,through the graduating valve 8, registers with a port 27, through themain slide valve '7; In the service application position of the mainslide valve, as shown in Fig. 3, the port 27 registers with a passage 28which leads to the atmospheric exhaust port 21.

Consequently,'when the graduating valve.8 is moved inwardly by flexingof the diaphragm 12,

fluid under pressure will be vented from the auxiliary reservoir to theatmosphere, and the venting continues until the auxiliary reservoirpressure has been reduced to a point, such that the differentialpressure between the brake pipe and the auxiliary reservoir will besufflcient to cause the piston 4 to shift the main slide valve 7 torelease position. As soon as the main slide valve moves toward releaseposition, the port 27 is,

moved out of registry with passage 28, so that further venting of fluidfrom the auxiliary reservoir is cut off. a

When the triple valve parts have been shifted to release position, uponsubstantial equalization of fluid pressures between the auxiliaryreservoir and the brake pipe, the spring 18 acts to return the diaphragm12 and the graduating valve 8 to their normal positions, as shown inFig. 1.

While one illustrative embodiment of the in vention has been describedin detail, it is not my intention to limit its scope to that embodimentor otherwise than by'the terms of the appended claims.

Having now described my invention, What I to secure by Letters 1. In afluid pressure brake, the combination with a brake pipe, an auxiliaryreservoir, a brake ment movable relatively to said piston upon anincrease in brake pipe pressure for operating said graduating valve tovent fluid from the auxiliary reservoir.

2. In a fluid pressure brake, the combination with a brake pipe, anauxiliary reservoir, a brake cylinder, and a brake controlling valvedevice comprising a main valve, 'a graduating valve and a piston foroperating said valves upon a reduction in brake pipe pressure to supplyfluid under pressure from the auxiliary reservoir to the brake cylinderto effect an application of the brakes and upon an increase in brakepipe pressure to release fluid from the brake cylinder, of a flexiblediaphragm associatedwith said piston and operatively connected to saidgraduating valve, said diaphragm being operated by an increase in brakepipe pressure to operate said graduating valve so as to vent fluid fromthe auxiliary reservoir.

3. In a fluid pressure brake, the combination with a brake pipe, anauxiliary reservoir, a brake cylinder, and a brake controlling valvedevice comprising a main valve, a graduating valve and a piston foroperating said valves upon a reduction in brake pipe pressure to supplyfluid under pressure from the auxiliary reservoir to the brake cylinderto effect an application of the brakes and upon an increase in brakepipe pressure to release fluid from the brake cylinder, of a flexiblediaphragm associated with said piston and operatively connected to saidgraduating valve, said diaphragm being operated, with the main valve inbrake application position, by an increase in brake pipe pressure tooperate said graduating valve and thereby vent fluid from the auxiliaryreservoir.

4-. In a fluid pressure brake, the combination with a brake pipe, anauxiliary reservoir, a brake cylinder, and a triple valve devicecomprising a main valve, a graduating valve having a movement relativeto the main valve and a movement relative to said piston, and a pistonfor operating said valves upon a reduction in brake pipe pressure tosupply fluid under pressure from the auxiliary reservoir to the brakecylinder to effect an application of the brakes and upon an increase inbrake pipe pressure to release fluid from the brake cylinder, of aflexible diaphragm carried by said piston and operatively connected tosaid graduating valve and operated by an increase in brake pipe pressurefor moving said graduating valve relatively to said piston to a positionfor venting fluid from the auxiliary reservoir;

'- CLYDE c. FARMER.

